David Oh is serious about running for mayor. The GOP is listening.

Philadelphia’s last competitive general election for mayor was 20 years ago, with the other races typically featuring low voter turnout and blowout victories for Democrats.

David Oh, the Republican nominee for mayor this year, wants to change that. His party is paying attention.

For two decades, establishment Republicans have held onto to their money and instead spent it on other races around the state.

But on Tuesday, they are throwing Oh a campaign fundraiser at The Union League, that South Broad Street bastion of old money and conservative politics.

That indicates that wealthy and powerful Republicans from around the state are paying attention to this year’s mayoral race, as Oh faces Democratic nominee Cherelle Parker.

» READ MORE: Here’s what Cherelle Parker has been up to since winning the Democratic nomination for mayor

Parker is heavily favored to win, given the city’s overwhelmingly Democratic electorate. But Oh, who formed a broad coalition of support as a City Council member, said he’s encouraged that influential Republicans believe in him enough to help.

“It’s reasonable to say these folks don’t just jump in on a whim,” Oh said.

The fundraiser’s hosts include some of the top names in the state GOP. They hope that a good showing for Oh will influence the outcomes of other races on the ballot — including City Council, in which Republicans are trying to fend off the progressive Working Families Party.

“How David Oh does in his race will greatly affect our races for City Council and city commissioner and also statewide appellate court races,” said Andy Reilly, a Republican National Committee member from Delaware County, with cautious optimism.

Oh, who resigned from City Council in February to run for mayor, said such fundraising events tend to come after Labor Day. If they happen at all.

“The fact that they’re popping up in August, it means someone has talked them into starting an engagement process,” he said.

It takes a measure of moxie to think you can be the first Republican mayor in Philadelphia in seven decades.

Oh knows the odds; Democrats outnumber Republicans 7-1 in the city.

He also knows how necessary it is to draw attention to his campaign.

“I think the problem in our city is that people are not interested in this race in the media because they think it’s over,” he said.

Host committee members for Tuesday’s event put up at least $1,000, while cohost tickets are $500 and sponsor tickets are $250.

Hosts include the party’s current state chair, Lawrence Tabas, a Philadelphia lawyer who typically keeps a low profile; Reilly and fellow RNC member Christine Toretti; Bob Asher, a former RNC member; local party chair Vince Fenerty; and former state party chair Rob Gleason.

Gleason, the driving force behind the fundraiser, is from Western Pennsylvania but has long pushed for a reinvigorated GOP in Philadelphia. He said he’s impressed by Oh.

Unified Republican support for a mayoral candidate has been absent since Sam Katz came close to a win against John Street in 1999 and 2003.

“I think he is the best candidate that we’ve had for mayor since Sam Katz,” Gleason said. “That’s a long time ago.” Gleason said he wants a “really good showing for mayor” ahead of next year’s presidential election, because Republican growth in the city will boost the party’s chances statewide in 2024.

“You will not be president of the United States unless you win Pennsylvania, Democrat or Republican,” Gleason said.

One factor in Oh’s favor: He’s the first long-term Republican to be the party’s mayoral nominee since Al Taubenberger in 2007. And Taubenberger ran an extremely collegial campaign that year, using it as a platform to build name recognition for a Council race four years later.

The Republicans fielded former Democrats Karen Brown in 2011, Melissa Murray Bailey in 2015, and Billy Ciancaglini in 2019. Those novices were all soundly defeated.

Another important factor for Oh — anything good for him trickles down as support for Republicans like Drew Murray and Jim Hasher, who are running for Council at-large seats. The party has incentive to boost the top of the ticket, if only for that.

“I think David is a good candidate,” Reilly said. “Whether it materializes into a real race for the mayor’s office, that remains to be seen.”

Oh has often been at odds with the Republican City Committee leadership and ward leaders. His name was cut from many sample ballots in the May primary after he backed a Council candidate who had clashed with the party.

Fenerty, the local chair, said Oh had turned around his relationship with the party’s ward leader, who cheered him at their summer picnic fundraiser earlier this month.

“He gave a very aggressive speech, probably the best speech he has ever given in his life, on all the points of why he is qualified to be mayor of Philadelphia,” Fenerty said.

Rousing speeches and receptive audiences make for good politics. But an underdog needs resources, too.

Bailey, who ran as a Republican against Jim Kenney for an open mayor’s seat in 2015, told Republican ward leaders that year she needed to raise at least $3 million to be competitive. She brought in less than $30,000 and won just 13% of the vote.

Taubenberger faced Michael Nutter for an open mayor’s seat in 2007 with a similar financial disadvantage. He raised $76,000 in the four months before that year’s election, compared to Nutter’s $2.9 million, and lost that race by a 4-1 ratio.

Parker, also a former City Council member, emerged from May’s nine-candidate primary with just shy of $64,000 in the bank as of June 5. She didn’t have the most money in the primary, but she built the political coalition that could win.

Those backers won’t have her go wanting, even if they see her election as mayor as a foregone conclusion.

Oh, a lawyer and former assistant district attorney, had envisioned a general election against a different Council colleague, Democrat Helen Gym, an ardent progressive who might have sent moderate Democrats looking his way. Gym finished third in May’s primary.

Oh ran unopposed in his primary and had just under $300,000 in the bank in early June. He’s betting on votes and maybe campaign contributions, too, from outside his party.

Unlike other Republicans in the city, who tend to look for pockets of support in South Philly and Northeast Philly, Oh won three terms on Council with a spread of support that covered more of the city.

“I am the most known Republican in the city,” he said. “I’m a Republican who gets crossover support from Democrats and independents.”